In the previously-cited application, a mold is disclosed which is adapted to simultaneously mold a closure having a threaded port, plus a separated threaded plug adapted for sealing the port. As the mold opens, the plug is screwed in the port so that the complete closure is provided in a single mold shot.
In this present application, a port closure, which optionally may be made in accordance with the teachings of the previous application, is disclosed in which the port closure may be opened for access to the container, without removal of the plug from the aperture, and at the same time reliably sealed by movement of the plug to another rotational position.
Threaded port closures are used for large cans, for example five-gallon paint cans, large containers of industrial chemicals, and also other large containers, for example brine barrels for the storage of fish and the like.
Typically, the plugs of the port closures must be removed to open the container. In many instances it would be desirable to open the container without removing the plug.
Also, in containers such as brine barrels, beer or root beer kegs, or the like, it may be desirable to open the container sufficiently to vent pressure from the container, or to determine that the liquid level in the container remains at the top. For example, water must be periodically added to brine storage barrels and the like.
By this invention, the plug closure of this invention may be opened without removal of the plug to add or remove contents of the container. For example, the container may be vented in this manner, or the closure may be utilized to determine whether the liquid in the container is still up to the top. An inwardly projecting plug of this invention may have an outwardly-facing recess which can receive flowing brine from the interior of the container when open and when the container is filled to the top. Otherwise, no brine or other liquid will flow into the recess of the plug, and in that circumstance, water or other fluid material may be added to fill the container to the top without removing the plug.
At the same time the plug may be removed whenever such is desired.